The present invention relates to a method and a circuit for transmitting spectrum-compatible high-definition television signal in a television signals transmission system, wherein frequency band separation technique and sub-sampling technique are employed.
Since late 1960 high-definition television (HDTV) system has been developed in Japan. There have been proposed various prototypes of HDTV systems such as Japanese MUSE (multiple sub-Nyquist sub-sampling encode) system, European HD-MAC system, AC-TV of DSRC spectrum- compatible HDTV system of Zenith, MIT system using sub-frequency band coding technique and SLSC of the Bell Lab. developed by the U.S.A. However, one of the problems to solve is to make a HDTV system compatible with a conventional color TV. In this point, the japanese MUSE system is incompatible with a conventional color TV. While the HDTV system of the AC-TV is compatible with a conventional NTSC color TV, the frequency must be extended.